Idiopathic intracranial hypertension (IIH) is a condition in which the pressure inside the skull rises without a tumour or any other obvious cause. It most often affects young women who are overweight and is dangerous because it can quietly damage the optic nerves. Seeing a doctor early gives you the best chance of protecting your sight.
What intracranial hypertension is
The brain is surrounded by cerebrospinal fluid, which creates a certain pressure inside the skull. In idiopathic intracranial hypertension this pressure rises, even though doctors find no tumour, no bleeding and no inflammation. The word “idiopathic” means the exact cause is unknown. The raised pressure presses on the optic nerves and on brain structures, so the main signs are headache and vision problems. The condition is sometimes called “benign intracranial hypertension”, but that name is misleading: without treatment the disease can lead to permanent loss of vision.
Causes and risk factors
- Female sex and an age between 20 and 45 — the largest group of patients.
- Being overweight and gaining weight quickly.
- Certain medications: excess vitamin A products, some antibiotics (tetracyclines), hormonal medicines, and corticosteroids when stopped abruptly.
- Endocrine disorders and hormonal imbalances.
- Impaired drainage of venous blood from the brain.
- Hereditary predisposition and some chronic diseases.
Symptoms
- A constant or worsening headache that often becomes stronger in the morning or when bending over.
- Brief episodes of blurred vision — sight “swims” for a few seconds, especially when standing up.
- A pulsating noise in the ears that beats in time with the heart.
- Double vision caused by weakness of the muscle that turns the eye outward (sixth cranial nerve palsy).
- Pain behind the eyes that gets worse when moving them.
- Gradual narrowing of the field of vision, which a patient may not notice for a long time.
- Nausea and sometimes vomiting during a severe headache.
Why this is a neuro-ophthalmic condition
Intracranial hypertension sits at the border between neurology and ophthalmology, because raised pressure strikes the optic nerves first. When examining the back of the eye, a doctor sees swelling of the optic nerve heads — the so-called papilloedema. The eye itself is healthy, while the cause lies in the brain, so the right specialist to assess it is a neuro-ophthalmologist — a doctor who combines knowledge of the eyes and the nervous system. They measure how much vision is affected, monitor the changes over time and refer you for the right treatment while the changes can still be reversed.
Diagnosis
- MRI of the brain — to rule out a tumour, bleeding and other causes of raised pressure.
- MR venography — to assess blood drainage through the venous sinuses of the brain.
- Lumbar puncture — a direct measurement of cerebrospinal fluid pressure and an analysis of its composition.
- Examination of the back of the eye to detect swollen optic nerve heads.
- Perimetry — a test of the visual fields that reveals early losses.
- Optical coherence tomography (OCT) — a precise measurement of swelling and optic nerve thickness over time.
Treatment
The main goal of treatment is to lower the pressure inside the skull and protect vision. Doctors prescribe medicines that reduce the production of cerebrospinal fluid, and patients who are overweight are advised to lose weight gradually, which noticeably improves the condition. In more difficult cases, repeated lumbar punctures or surgery are used to drain the fluid or relieve pressure on the optic nerve. The most important thing is early referral: the sooner treatment begins, the better the chance of fully preserving vision. Patients should have regular perimetry and OCT so the doctor can see whether the pressure stays under control.
When to seek help urgently
Seek help immediately if, together with a headache, your vision is deteriorating quickly, you have persistent blurring, your field of vision is narrowing sharply, you develop constant double vision, or your sight suddenly darkens. These signs mean the optic nerve is under threat, and delay can lead to irreversible blindness. It is better to be cautious and see a doctor the same day.
The German Eye Clinic will help you understand the causes of raised pressure and protect your sight. Call 0 800 507 670 or visit the “Neuro-ophthalmologist consultation” service page.
